Study On The Fate Of Nitrogen Of New Μrea In Winter Wheat-Summer Maize Rotation System

In order to study the effect of new urea on soil nitrogen transformation and nitrogen fertilizer direction in agricultural production activities,this study selected farmland soil,represented by Xinji as the research object,using static culture system in laboratory,combined with field test and ¹⁵N micro area test.The effects of different new types of urea on N₂O emission,ammonia volatilization and nitrogen absorption and utilization were investigated,and the direction and aftereffect of nitrogen fertilizer under the wheat maize rotation system were traced.Screening high efficiency and high yield nitrogenous fertilizers has important guiding significance for the popularization and application of new urea in agricultural production.The specific findings are as follows:（1）The cultivation test showed that all treatments reached the peak of N₂O emission on the second day,and the peak value of N₂O emission of urea control was the lowest,which was only 20168.1 g N/kg/d.New urea and urea were supplemented with urease inhibitors（HQ）or nitrification inhibitors（NP）.The ammonia volatilization rate was at the second peak and then decreased slowly.The volatilization rate of humic acid urea was the lowest,which was 0.58 kg/hm².Compared with ordinary urea,the cumulative N₂O emissions of three new types of urea,such as urea control,energy concentrated urea and humic acid urea,were significantly reduced by 58%,53.5%,58.7%,and the cumulative loss of ammonia volatilization decreased by 55.4%,53.1%,58.1%,but all higher than that of urea or HQ.During the incubation period,soil NO₃^-content was significantly correlated with N₂O emissions.Soil NH₄⁺content was significantly correlated with ammonia volatilization.（2）The large area test showed that the grain yield of the wheat treated with nitrogen treatment was significantly higher than that of the non nitrogen treatment.The yield of the urea controlled urea was the highest,8758.5 kg/hm²,and the urea was 8254.5 kg/hm²,and the urea in the humic acid was the lowest in the three new types of urea,which was 8217kg/hm².Compared with ordinary urea,the utilization of urea,urea and humic acid in urea nitrogen fertilizer increased by 116.3%,29.3%and 28.6%,and the highest utilization rate of urea controlled urea was 35.9%.The use of nitrogen in the upper part of the ground was as follows:grain>straw,in which the effect of urea control on nitrogen absorption was the most significant,the nitrogen value of its grain was 178.5 kg/hm²,and the nitrogen value of the straw was 64.5 kg/hm².The ¹⁵N microzone test showed that the highest yield of winter wheat in the three new types of fertilizer with urea control was 9025.5 kg/hm²,the energy of the energy gathering net was 8943.4 kg/hm²,and the lowest humic acid was8212 kg/hm².The efficiency of nitrogen absorption and utilization of urea controlled urea was the most prominent.The total nitrogen utilization rate of urea,urea,urea and urea+NP increased by 28.2%,10.8%,14.3%and 3.5%.（3）The content of nitrate nitrogen in soil of control urea,humic acid urea,energy net urea and universal urine+NP mainly exists in the surface soil of 0²0 cm,and the percentage of ¹⁵N atom in 0⁴0 cm was the largest,and its content was greater than that of ordinary urea;the content of ordinary urea nitrate nitrogen was accumulated in 80¹00 cm,and the ¹⁵N percent superoxide percentage was obviously higher here.The soil nitrate nitrogen was reduced after the following corn was mature,and the ordinary urea was obviously prominent at 100¹20 cm,and the other nitrogen treatment 0²0 cm accumulated the maximum nitrate nitrogen.In general,the total direction of nitrogen fertilizer after winter wheat harvest:crop absorption>soil residue>loss;in winter wheat summer maize rotation system,the later stubble corn can absorb nitrogen fertilizer from the soil of the previous stubble wheat,showing as follows:grain>straw;but the difference of the utilization ratio of residual nitrogen fertilizer in each treatment was not obvious.In summary,the new urea performed better in terms of crop yield,nitrogen uptake,and nitrogen use efficiency,and it had lower pollution to the environment.The effect of urine combined with NP,HQ was second,but both were superior to those of the urinary treatment.In the new type of urea,the loss of urea had obvious advantages in the winter wheat-summer corn rotation system in North China.It was an efficient and high-yielding type of nitrogen fertilizer and could be used as an important nitrogen fertilizer in local agricultural prodction.